The present invention is directed to a method and apparatus for providing a locked closed subsurface safety system for protecting petroleum reserves from undesired intervention and/or sabotage.
It is the practice of most safety systems to feature the ability to apply hydraulic pressure or electrical current through a control line to open a downhole safety valve for well production and upon release of this system the valve will close, ceasing all production of any well fluids. However, this very procedure provides the means by which a saboteur could hydraulically or electrically lock open the safety valve from the surface before setting fire to a free flowing well. And in wells where no safety systems exist the well will usually end up burning itself out when the fuel feeding the fire is depleted or until appropriate extinguishing techniques have been applied.
Therefore, the present invention is directed to a surface controlled locked closed subsurface safety system which will close a downhole safety valve and prevent the valve from being reopened through the control line. The valve can only be reopened by conventional wireline procedures which require moving a rig onto location and opening the valve through the interior bore of the production tubing, which requires considerable time and effort. Thus, the present invention protects petroleum reserves from undesired intervention and/or sabotage.